Hot water vacuum extraction machines, or as sometimes mis-named "steam cleaners," have come into vogue for home use as a result of commercial exploitation of applicant's patented concepts exemplified by applicant's U.S. Pat. Nos. 3,896,521 and 3,911,524. In the machine illustrated and described in U.S. Pat. No. 4,122,579, the steam cleaner employs a dump bucket, and in addition a soap tank, both elements being mounted within the upper half of a two part molded housing functioning as an enclosure for the internal components of the vacuum machine. Water and detergent are placed normally in the soap tank and an immersion heater within that tank heats the detergent containing water to an elevated temperature. Additionally, an internal water pump draws the detergent containing water from an outlet at the soap tank and forces it through a flexible tube or hose to an atomizer nozzle on a wand supported head, whereby a stream of hot detergent containing water issues from the nozzle in mist form, sometimes inaccurately referred to as "steam." The machine is normally employed in the wet cleaning of rugs with the detergent containing water and entrained dirt from the rug picked up by a vacuum head mounted to the end of the wand and returned to the machine carried dump bucket. This is achieved by use of an internal vacuum pump which communicates with the interior of the dump bucket via a hollow riser tube, creating a vacuum pressure within the interior of the dump bucket and external air rushing through the vacuum wand draws the detergent containing water and the entrained dirt into the interior of the dump bucket 12 where it accumulates. The air is separated from the water and entrained dirt within the dump bucket interior, the air passing through the riser tube by way of the induced suction due to vacuum pump operation with the air discharging through an air discharge pipe leading from the vacuum pump assembly casing and through the bottom of the lower half of the steam cleaner housing.
Necessarily, in order to prevent the electric motor driving the vacuum pump within the vacuum pump assembly casing from burning out or overheating, there is a requirement to cool the motor windings. This has been accomplished in the past by mounting the vacuum pump assembly such that its lower end projects through or is flush with an opening of similar diameter formed within the bottom wall of the steam cleaner housing lower half. Further, the lower end of the cylindrical vacuum pump assembly casing bears openings permitting air to be sucked up from beneath the machine and forced over the motor windings by means of a fan fixed to the lower end of the motor shaft and rotatable therewith. The motor rotates in a direction such that the air is sucked into the interior of the vacuum pump assembly casing through its lower end and the cooling air is forcibly discharged through a series of perforations or openings within the cylindrical sidewall of the vacuum pump assembly casing. The air enters the interior of the machine housing, and passes exteriorly of the unit through openings within the side of either the upper or lower housing halves.
While the vacuum pump assembly provides some cooling to the motor windings and maintains the interior of the steam cleaner housing to an acceptable low temperature, there is a tendency, particularly where the unit operates on surfaces bearing an accumulation of water, for water to be drawn into the air inlet at the lower end of the vacuum pump assembly casing, resulting in damage to the motor winding and, under some circumstances, the rendering of the vacuum pump inoperable. Further, while the temperature to which the components of the steam cleaner were subjected is reduced by the cooling air flow within the housing itself as well as the cylindrical casing of the vacuum pump assembly, the electric motor has not operated at its most efficient temperature. Further, over time, there exists the possibility of deterioration of the components interior of the housing due to the relatively high temperature experienced by those components.
It is, therefore, a primary object of the present invention to provide an improved water vacuum extraction machine in which the electric drive motor for the vacuum pump, as well as all of the components within the interior of the machine housing, operate at substantially reduced temperature from prior known machines, and wherein the effectiveness of air flow through the motor is appreciably increased, thereby eliminating hot spots.
It is a further object of the present invention to provide an improved hot water vacuum extraction machine having a highly effective air cooling arrangement for a sealed, cylindrical vacuum pump assembly, and in which positive air flow functions during machine operation to effectively prevent water from entering the area of the motor winding of the vacuum pump.
It is a further object of the present invention to provide an improved reverse flow fan for a vacuum pump assembly employable within a hot water vacuum extraction machine, in which the cooling efficiency of the motor is enhanced, and wherein air turbulence in the area of the fan blading is reduced to reduce the recirculation of exhaust air and wherein smooth exiting of the exhaust air is accomplished with minimum back pressure.